Ventilation and fluid control systems are increasingly used in buildings, including residential, office, commercial, and industrial buildings, sometimes combined with fire or smoke protection equipment for occupant comfort and safety and also for manufacturing processes. Dampers and valves are used to control the volume of flow of air and fluids from no flow to full maximum flow. These damper/valve air and fluid control systems include, but are not limited to, those used in electrical power stations, chemical manufacturing operations, food and beverage processing, liquid gas supply and disposal, water supply and disposal, Heating, Ventilation, and Air Conditioning (HVAC) systems, etc.
The air flow in HVAC and manufacturing process ducts are typically controlled by damper assemblies, or dampers. Dampers are used for the control of airflow to maintain temperatures in air-carrying ducts. Dampers are produced in a variety of sizes, shapes, and styles for installation in rectangular or round ducts. Dampers generally have a connecting rod or shaft, often called a jackshaft, which is connected to the vanes, or blades, of the damper. The damper may have a single blade or multiple interconnected blades that move in unison. Depending on the damper configuration, the jackshaft connecting rod may be connected such that linear movement of the connecting rod causes the damper blades to open or close. In other embodiments, dampers equipped with a shaft, or jackshaft, are arranged such that rotary movement of the jackshaft causes the damper blades to open or close, but an alternate, older technology, approach is to connect a crank arm to the shaft, or jackshaft and use a linear movement to open or shut the damper blades. Round dampers are usually of the butterfly type having a single round disk connected to a rotating shaft.
Control valves throttle the flow of a fluid by having their plugs move in their valve bodies to block the fluid flow at one end of movement and open the flow at the other end of movement. The valve plug may have a variety of shapes, either symmetrical or asymmetrical, and may be connected to a stem and seal that exits the valve body to allow an actuator located outside the valve to position the valve stem and plug. Typically, the seal is designed to have secure contact with the valve body stem and the valve body stem outlet such that it prevents fluid from leaking out of the valve while the valve is operating at its rated static and differential pressure ratings. Some control valves, such as globe and gate valves, require linear stem movement to fully open and close the fluid flow, and other types, such as ball, butterfly, and shoe valves, require rotary movement to fully open and close the fluid flow.
In a typical HVAC or process control application, the damper jackshaft or valve stem is operated by an actuator. The actuator is an assembly that generally includes a motor with some type of coupling apparatus, driven by the motor, which can be attached to the jackshaft or valve stem for the movement thereof.
Embodiments of the present invention represent an advancement over the state of the art with respect to damper and valve actuator assemblies. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.